It seems these AC cables are being praised in just about every HI-Fi magazine I pick up. Aparently they provide better timing (no, I don't know what that meant either), better dynamics and deeper bass. At $2500 a piece they better had.

I'll get to the point now. I don't understand why the cable to the power supply in the component (amp, CD player etc) would have any effect on the sound. The electricity runs though all different kinds of crap cables to get to your house and somehow placing 2 meters of very expensive cable at the end of that chain make a different? I don't think so. Sure, good quality cable to hook everything up is vital - after all it's your actual audio that's runiing though them. But an audiophile mains lead?

Can some one please tell me a logical/scientific explanation of how this works? Is there one? Anyone actually heard the difference a good power cord caqn make to their system? It seems like a load of shit to me but there is just too many reviews and publicity for it to be completely false.

Anyone actually heard the difference a good power cord caqn make to their system? It seems like a load of shit to me but there is just too many reviews and publicity for it to be completely false.

Tony

What difference would 'hearing' the power wire make unless it was done under strict controlled circumstances(DBT or ABX) and the test results scrutinized for errors? Psychological ias will effect perception.

As far as 'just too many reviews and publicity for it to be completely false'.

Uhm, popularity and mass propogation of bullsh_i_t just equals very popular and propogated bullsh_i_t. :-)

Can some one please tell me a logical/scientific explanation of how this works? Is there one? Anyone actually heard the difference a good power cord caqn make to their system? It seems like a load of shit to me but there is just too many reviews and publicity for it to be completely false.

I think it's impossible to answer part of your question without violating TOS #8. But I'll try to answer the part I can answer by quoting the available reasonable arguments, none of which I have verified. IMO, in audio there's very little you can rule out on the basis of simplistic technical arguments. A/C power cords are a case in point. Still, $2500 power cords are absurd and completely unjustifiable.

Do they make a difference in the sound? Sorry, can't anwer that (TOS#8). Is it possible that they do? Absolutely. Expensive power cords can, in principle, act as filters for high frequency nasties on the power lines. These nasties are often generated by digital equipment, sometimes in your stereo system. CRT computer monitors are also very bad. The worst source in my house is a cheap range with a digital control panel. A cord with a ferrite-impregnated jacket can act as a filter for high frequencies. I'm not claiming that the cord you mentioned actually does this, but it's possible. Also, heavy shielding can reduce the nasties that could get into the supply via radiation, via the cord acting as an antenna. It's well documented (see, for example, the classic book by H. Ott) that such nasties can adversely affect the operation of various types of electronic equipment.

Another factor is that by modeling an typical amplifier circuit you can see that the peak current in the power cord far exceeds the RMS value. That's because the power supply only "recharges" at the top of the A/C cycle. You can get some rather intense current peaks, exceeding the RMS value by a factor of 10 or 15. The result can be a very significant reduction in voltage as a result of resistive losses in a typical 18 gauge power cord and its associated imperfections (poor crimps, etc.). These very fast current pulses can also create high-frequency nasties, which can feed back into the A/C in the absence of shielding and filtering.

Those are (some of) the arguments, and I find them reasonable, though they certainly don't justify paying $2500 for a power cord. I don't know electronics that well, but I have a physics Ph.D.

Those are (some of) the arguments, and I find them reasonable, though they certainly don't justify paying $2500 for a power cord. I don't know electronics that well, but I have a physics Ph.D.

This all comes down to basic electrical/rf laws, though. The hi-end proponents specifically make their claims on supposodely 'mysterious' or 'unknown' variables. But any properly designed audio applanec should have an effective filter in the power supply. Personally I would question the value and engineering of audio equipment that required a special pwer cord that had special filtering properties in order to function properly.

This all comes down to basic electrical/rf laws, though. The hi-end proponents specifically make their claims on supposodely 'mysterious' or 'unknown' variables. But any properly designed audio applanec should have an effective filter in the power supply. Personally I would question the value and engineering of audio equipment that required a special pwer cord that had special filtering properties in order to function properly.-Chris

True, it all comes down to electrical/rf laws, but I don't know about "basic". Finding the answers to some of these questions would require careful experimentation and possibly modeling. As for questioning the value and engineering of audio equipment that requires a special power cord to function properly, I agree with you up to a point. There's some very expensive, very poorly engineered equipment out there. But I'm less inclined towards the polarized view this implies: good engineering wouldn't benefit at all, lousy engineering might. There's a lot of middle ground here between great and lousy, and many widely available products may fall in the middle...and consequently may benefit the extra filtration/reduced losses an aftermarket power cord might provide. There are some easy tests you can do, though visual ones are often easier than audible ones. Try using a good A/C filter on your television while watching a DVD. If your power is clean you may not notice a difference. But if the power isn't clean ... If A/C nasties can interfere with a DVD player's electronics, why not with a CD player or an amplifer?

Finding the answers to some of these questions would require careful experimentation and possibly modeling

WIth issues such as this, I tend to follow a logical methodology for consideration: IN this case, like many others: a claim is made, no substantiation is has been produced to confirm the claim/suspicion. I just can't take it seriously, especially with claims that have been around a while with no substantiation. If tht substatiation appears; I'll glady review it and accept if valid. I can not possibly assume or test/analyse for every possibility, since this would open up one huge can of worms you can't possibly count.

QUOTE

Try using a good A/C filter on your television while watching a DVD. If your power is clean you may not notice a difference. But if the power isn't clean ... If A/C nasties can interfere with a DVD player's electronics, why not with a CD player or an amplifer?

1st, I'm not comfortable discussing video implications. I have not researched, nor am I interested in video. However, since video and digital video devices operate at much higher frequencies then most audio equipment(SACD obviously being an exception), then it would seem to be rational that they would be more sensitive to high frequency interference from RF, etc as opposed to audio equipment that usually operates a much lower frequencies. Again, I have no knowledge of specific implicatinos on video.

Every circuit inside an amp runs on DC. If the power supply is doing it's job (producing pure DC) and the amp layout is good (that is...PS is as far way as possible from the circuitry...to eliminate any 50/60 Hz hum). It's what inside the amp that counts.

xen-uno

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No one can be told what Ogg Vorbis is...you have to hear it for yourself- Morpheus

WIth issues such as this, I tend to follow a logical methodology for consideration: IN this case, like many others: a claim is made, no substantiation is has been produced to confirm the claim/suspicion. I just can't take it seriously, especially with claims that have been around a while with no substantiation. If tht substatiation appears; I'll glady review it and accept if valid. I can not possibly assume or test/analyse for every possibility, since this would open up one huge can of worms you can't possibly count.

I recall that this is not only WmAx' point of view. This is the very foundation of this discussion board. Claims about sound quality are not taken into account unless proven (see the Terms of Service, article 8, for explanations).

I recall that this is not only WmAx' point of view. This is the very foundation of this discussion board. Claims about sound quality are not taken into account unless proven (see the Terms of Service, article 8, for explanations).

Not sure if this is directed at me, but for the record, I've made no such claims.

If the power supply is doing it's job (producing pure DC) and the amp layout is good...

Once again, here's this polarized viewpoint. Perhaps this is a hazard of the (otherwise very sound) ABX mindset. Something is either one way, or the other. I think it's safe to say (and I'm making no claims here that violate TOS8) that the perfect circuit hasn't been designed yet. Why the assumption that something is either okay or not okay? What about the middle ground.

Hey, I know what it is. It's digital! All those ones and zeros! You know, in real life (not counting quantum mechanics) there's no such thing as digital! Every signal has a rise time, and usually an overshoot! I'm being metaphorical here, not literal...there's always a middle ground, and I believe that's where most available consumer electronics lie--in the middle, with adequate but imperfect power supplies, and adequate but not impervious circuit layout. Why should we assume that they're either perfect or defective? Where's your evidence?

Well...either you'll get an audible 50-60 Hz humm...or you won't. Pretty much black & white...no middle ground. If someone routinely runs power cords directly underneath, close to the sides, or on top of equipment, then these $$$ cords are for them (by virtue of the shielding...if present). The standard rule as we all know, is to separate power cords from signal carriers, and to keep those power cords away from the equipment as much as possible. Power supplies don't have to be perfect (as as you pointed out, seldom are)...just good enough to produce reasonably flat DC. A minor AC component (of the DC) probably does exist in consumer grade PS's, but is inaudible (if not, then it's a bad PS).

xen-uno

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No one can be told what Ogg Vorbis is...you have to hear it for yourself- Morpheus

I believe that's where most available consumer electronics lie--in the middle, with adequate but imperfect power supplies, and adequate but not impervious circuit layout. Why should we assume that they're either perfect or defective? Where's your evidence?

If it is defective, it must be proven. If it is perfect, it can't be proven. That's why we look for proofs of defective devices.So far we don't have any proof, with listening tests, nor distortion measurments, that power cables can change the sound of a device. And, following the theory, it is unlikely that they can. We have such proof for speaker cables under special conditions, but nothing yet for modulation cables, power supply orientation, digital cables and a lot of other doubtful audiophile tricks.That's why we apply the skeptical approach : first find a fact, then explain it. Trying to explain a fact before proving its existence is, in average, a loss of time, because sometimes the fact is true, and sometimes it is false.

QUOTE (jaustin @ Aug 3 2004, 09:10 PM)

Not sure if this is directed at me

No, I just found that WmAx could have formulated it in a more definitive way, instead of presenting it just like his own casual point of view.

The cable can be modeled quite nicely using an equivalent circuit to understand the first order performance effects. I might be able to justify some additional $$ for styling or some placebo-BS if I at least understood what the cable was doing at the LRC level. Heck, given that there are not any specifications for RCA jacks, there is some value just in good connectors that don't fall off.

To me, any discussion of audio cable should begin with the LRC data and the input / output impedance of the source and destination audio components. Then we can model the first order effects and get on with the rest. For example, an audiophile cable could make bold sonic claims and actually have a high capacitance which when used with certian audio components may roll off the high frequency response. This could explain it sounding different ("better" or "worse") than another cable in that circuit.

Is it too much to ask audio/video companies to publish these basic specifications? Do they not do it because it will expose the "BS" (cynical reason), because they don't know the specifications (more cynical?), because they don't think it matters (probably true for gullible customers), because nobody requires them to...? Would you spend $2,500 on any other audio component without ANY technical specifications other than length and connector type?

Until the industry begins including basic LRC data they will have a credibility problem to me - but maybe they like it that way.

If it is defective, it must be proven. If it is perfect, it can't be proven. That's why we look for proofs of defective devices.

With respect--and I mean that--both for you and for the rigorous standards applied on this board, I'm really not sure this makes sense. "Defective" is an intellectual construction. By extension, so is "perfection." If it is the absence of perfection, then (not meaning to get religious here) everything is defective, by definition. No proof is necessary: Everything is defective, to a greater or lesser extent. The key question is, can you reliably distinguish a difference, whether of character or of absolute quality? But I digress. Your definition of "defective" is inherently subjective: it depends on your hearing and jugement. Doesn't it make more sense, then, merely to speak of differences in quality, or even in character, rather than to embrace this perfect/defective binary?

A second question, of great significance to this board, but of far less fundamental significance, is: can you prove that you can hear it? Because to know something, and to be able to prove it, are quite different, as I think we all know from our everyday, nonscientific, nonaudio existence. Perhaps we COULD prove them, but we know them no less well in the abence of proof.

Your definition of "defective" is inherently subjective: it depends on your hearing and jugement.

Yes. For some people, Musepack -q5 is transparent. For other people (well, to make it short, for Guruboolez and Xerophase), it is not.

QUOTE (jaustin @ Aug 4 2004, 03:16 AM)

Doesn't it make more sense, then, merely to speak of differences in quality, or even in character, rather than to embrace this perfect/defective binary?

This is the next step. For example, discussing a problem sample with MP3, first, the ABX test is run. If it is successful, it shows that the difference is audible. Then, we can discuss what difference : noise, drop out, ringing, annoying or not, where in the file...

QUOTE (jaustin @ Aug 4 2004, 03:16 AM)

can you prove that you can hear it? Because to know something, and to be able to prove it, are quite different, as I think we all know from our everyday, nonscientific, nonaudio existence.

We try to help people to prove it. It is sometimes difficult, but it is very interesting.

QUOTE (jaustin @ Aug 4 2004, 03:16 AM)

Perhaps we COULD prove them, but we know them no less well in the abence of proof.

I disagree. Many things that I knew without proof turned out to be false. Just a product of my imagination. I thought that I knew them, but I was wrong. Some other things that I knew were true. It is always possible to prove something that we know and that is true, if we spend enough time and effort in the process. Sometimes the proof is not worth the effort. I think that it is what you call "something we know but can't prove".

I disagree. Many things that I knew without proof turned out to be false.

I think we're getting down to some fairly subtle--yet very meaningful--philosophical questions here. I can't disagree with anything you've written; absolutely there are deeply held commitments--held without proof--that change profoundly over time. Yet I can't help thinking we cripple ourselves by disbelieving things we KNOW are true, just because we haven't done a statistically significant ABX test and because we know some portion (minority?) of them will later turn out to be false. Yet as a scientist, in my (former) professional life (I no longer earn my living by doing scientific research) it's necessary to require proof. I wonder if that's not the crux of the issue here: this is largely a board for professionals, which do, and ought to, require proof. The audio mags that promote (eg) $2500 cables are for hobbyists, people for whom audio is not a part of their professional lives. It's natural for professionals to embrace a higher standard of proof. Of course the people who do reviews are also professionals, so it's reasonable to ask whether they should embrace a more rigorous standard. The answer, I think (as I've partly indicated in a different thread) is that 1. rigor is prohibitively difficult, and 2. that sort of rigorous approach may not be consistent with a magazine's editorial goals, even if (even though) there may be NO corruption and only the best intentions.

I think we are very close to agreement here. In the audio realm, things are indeed very tricky, and people--even widely published audio reviewers--probably are not as cautious as they should be. (Though everyone should carefully consider Stereophile's measurements, which often contradict dramatically, and are always run alongside, their subjective reviews, before reaching final conclusions about THAT magazine).

But by the same standard, or a similar one--we ought not to let a healthy skepticism and a scientific approach calcify into a closed mind and narrow expectations. The idea that a power cord could improve the sound of a DC device is counterintuitive. It's natural to be skeptical. But it's also appropriate to be skeptical, not of theory, but of our ability to apply it directly and carefully in drawing such conclusions. I will never pay $2500 for a power cord, but I don't believe there's anyone on this board who knows enough to rule out the possibility that it might make a positive difference. (Speaking here to the board in general, or at least to those who are following this thread:) Remain skeptical, apply your rigorous testing wherever possible, but don't let a superficial knowledge of science--and despite way too many years spent in graduate school, my knowledge, too, of these issues is superficial--get in the way of an open mind.

Does the sum of these imperfections allow you to detect the presence or absence of one single imperfection? Do the other imperfections make it easier or harder to detect the single imperfection under scrutiny?

At best, you can say that the hum may be inaudible a your preferred listening volume through your speakers in your room to your ears when listening to your music. How do you know it will be inaudible at my preferred listening volume through my speakers in my room to my ears when listening to my music?

You can say when it probably will be audible, and you can say when it probably will not be audible. However, in between there is a great wide world of possibilities! Much equipment will be in that range; probably not for hum, but for less easy to control issues e.g. interference.

You do have to be careful of bullshit, but you also have to be careful of adopting this simplistic "back and white" mindset, which just isn't how the real world works!

Other wise you become like the man who asks "Is it raining?" and will only accept a "yes" or "no" answer: Allowing "not much", "it's just stopping" and "it's about to chuck it down" would have been much better!

Yeah...whatever. You'll either hear it...or you won't. I don't care what you turn yours up to...or what anyone else turns theirs up to...they'll either hear it...or they won't. Read the thread title again so that we're on the same page, because in my previous post I state the conditions where these cables may be useful. It would be highly unlikely that the dimunitive effect of a properly run standard power cord would push humm (and other forms of interference) into the audible range (even when compounded by xxx number of cords). Theoretical?..forget about it...I speak from practical real world experience.

xen-uno

This post has been edited by Xenno: Aug 4 2004, 16:14

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No one can be told what Ogg Vorbis is...you have to hear it for yourself- Morpheus

I recall that this is not only WmAx' point of view. This is the very foundation of this discussion board. Claims about sound quality are not taken into account unless proven (see the Terms of Service, article 8, for explanations).

Yes, on the discussion board itself. The board doesn't assert that these claims shouldn't be taken into account, only that such claims can't be made on the board itself. And unproven claims about technical things can be made; it's only unproven claims about sound quality that can't be made. So Mr. Austin is staying within the rules, very nicely if I may say so.

Well...if you do get hum, buy a $4 length of steel conduit and run the power or signal wires through it. Shielding problem solved and you save $2496. If you still get hum, get some cheap 16 gauge and run a ground to each of your audio components. There are easier ways to deal with these types of problems than Nordost would have you believe.

And yes, the effect of a 2m power cable is insignificant compared to the noise picked up in the 200km of cables between you and the power station, or noise added from every transformer between here and there. Scientific proof? The length of that cord in the above example represents .0005% of the total length of the circuit, which rounds neatly down to 0. No need to get any more technical than that.

Anyone who still wonders why people buy these things? It's easier to understand when you consider that it's the same reason you buy diamonds, good luck charms, ionic bracelets, magnetic bracelets, lawn gnomes...and a host of other junk. People can be easily fooled when it comes to the relative value of consumer goods if manipulated correctly.

The best part about luxury audio cables is where they come from...they would have you believe that unprecidented research and development led to the design of these cables, and they were built with the finest materials and processes that noone else has...but the reality of the matter is that they _all_ buy their cables pre-made from a number of asian manufacturing conglomerates from basically a catalog. They occassionally order a few custom cosmetic changes, the finished cables are then manufactured, shipped to the 'Nordost' office and then the brand name is silkscreened on. How much would a $2500 cable like these cost directly from the manufacturer? If I had the catalog and inquired about the price I could probally find the cost of this specific cable, but from experience I'd say you'd be looking at well under $1 per cable, more like $0.10/foot + $0.04 per end in quantity. I'm not exagerating either.

My friend is actually a registered distributer for asian sources and managed to get a quote for a specific nordost brand square cable for the sake of disproving a group of audio zealots...unfortunately the post has long since expired. You need the manufacturer catalogs to find a specific brand and model of remarked cable, but I assure you, they exist.

Anyway, the point was to show how impressive the profit margins are on these cables. This goes a long way to demonstrate how a company can make money by selling only a few products to a very small handfull of gullible people.

And yes, the effect of a 2m power cable is insignificant compared to the noise picked up in the 200km of cables between you and the power station, or noise added from every transformer between here and there.

Nope. It varies from model to model, but transformers generally have a fairly narrow bandwidth. They filter out most radio frequency (and above) noise. Lucky for us. So the step-down transformer at your house is likely to filter much, but not all, noise from the outside world. Furthermore, if the cord filters noise... (of course there are other ways of doing that...and as I've said, I'd never recommend a $2500 power cord to anyone).

QUOTE

Scientific proof? The length of that cord in the above example represents .0005% of the total length of the circuit, which rounds neatly down to 0. No need to get any more technical than that.

Power delivery systems (in the U.S.) are designed to deliver 120 V A/C TO THE RECEPTACLE at the full rated power. Typical house wiring is 12 or 14 gauge. The typical power cord is 18 gauge. Currents drawn by an amplifier during the re-charging of the power supply can reach values that are 10-15 times larger than the RMS value. That can mean significant voltage drops in those 18 gauge power cords, perhaps 5 Volts, OVER THE LENGTH OF THE POWER CORD. Yes, there will be voltage drops in the household wiring, too. But they will be smaller if the wiring is up to code.

And yes, you can solve this problem (or greatly mitigate it) by buying a shielded 14 guage power cord from Belden, that will cost somehwere around ten bucks. Like I said, I'm not advocating $2500 power cords. What I'm trying to do is to convince folks not to rely on old saws based on the clumsy application of science insufficiently understood. I'm all for testing, but keep an open mind. There's plenty of snake oil in hi-end audio, but it's a lot harder than you seem to think to tell the good guys from the bad guys.

I'll close by not making any claims about the positive effects I might (or might not) have heard when I switched out my Belden 14 gauge shielded for a budget hi-end power cord (which cost about 5% what the cord being discussed here costs). I won't make any claims because to do so would violate TOS8.